“IDENT/IAFIS” is the agency’s internal name for the immigration database.

California Watch asked ICE on Friday what specific federal laws or regulations make interoperability “mandatory.” Virginia Kice, an ICE spokeswoman, said she was unable to receive an answer from the agency’s legal counsel before the weekend.

The National Day Laborers Organizing Network, working with the Center for Constitutional Rights and the Cardozo Immigration Justice Clinic, obtained the heavily redacted communications through a Freedom of Information Act lawsuit.

The e-mail exchanges primarily focus on how local agencies can withdraw from Secure Communities. Though ICE officially has an "opt out" option, it does not allow jails to discontinue fingerprint scans. Instead, local agencies can choose not to be notified when the database identifies an illegal immigrant; ICE still receives that information and can begin the process of removing the individual from the country.

In the back-and-forth emails, ICE officials only once referenced a law or regulation that might make the fingerprint identification system mandatory. And that came in the form of a question from Jerry Brown [PDF], then California’s attorney general.

Federal Immigration and Naturalization law (specifically U.S. Code Title 8, Section 1373) is referenced in an e-mail John Morton, ICE’s director, wrote to his chief of staff in July regarding plans to have drinks with Brown.

Brown had questions about the agency’s operations in California. Among them was whether county sheriffs are allowed to withdraw from Secure Communities. “I think he is thinking about whether a refusal to participate violates 1373 or if there is some requirement of participation,” Morton wrote.

That code prohibits government agencies and officials from blocking access to “Immigration and Naturalization Service information regarding the citizenship or immigration status, lawful or unlawful, of any individual.” When the INS merged into the U.S. Department of Homeland Security in 2003, most of its operations were reorganized under ICE.

Brown had prevented San Francisco from opting out of Secure Communities months before his scheduled meet-up with Morton.